The electric vehicle controller should be comprehensively designed taking into account the actual use of the battery and the motor. The relationship between the battery, the controller, and the motor should be fully considered, and they should be designed as a comprehensive system to obtain a more ideal Electric vehicle controller. It should not be a commercially available electric vehicle governor that has functions such as stepless speed regulation, brake power failure, and soft start. In view of the actual use of electric bicycles, we have improved the design of the brushless electric bicycle controller and added the following functions:
1.Make the electric vehicle controller have output short-circuit protection function The controller can realize the direct short-circuit protection of the output terminal, even when the motor is at the highest speed action (the highest voltage is usually output at this time) directly short-circuit the output terminal of the controller, the controller can also be very reliable protection. During protection, the circuit automatically reduces the output current to protect the safety of the battery. At this time, the current is about 0.3A, and the status of the output terminal is checked at any time. When the output terminal is faulty, the controller can automatically resume normal control with self-recovery function Therefore, the controller has self-protection capability, which improves the safety of the controller and the storage battery, and also improves the tolerance to the fault of the motor itself. In view of the actual use of electric bicycles, locked-rotor is one of the possible working conditions. If the controller can reliably protect the output terminal from short-circuit, the controller can also protect and protect the motor when the motor is locked. And battery safety. If there is only a controller with current limiting function, it will output a large current (such as current limiting 14A). These make the battery (capacity 12AH) in a large current discharge state (14A), which will affect the service life of the battery. In addition, the large current flowing through the motor windings will cause the temperature rise of the motor to rise for a long time, causing the winding insulation to age, which may affect the life of the motor, and burn the motor.
2.Adopt double closed loop control system The controller adopts a double closed loop control system (brushless: speed/current double closed loop, brush: voltage/current double closed loop). Due to the existence of the current loop, the current can be limited, that is, it can protect the electric vehicle in various normal conditions. Under operating conditions, the maximum current output value will not exceed the set current limit value and realize automatic current limiting, so that under any operating conditions, the battery will not have a discharge process that exceeds the set value current, which ensures the safety of the battery. In addition, due to the cooperation of the double closed loop, the motor can achieve the most ideal starting process and acceleration process, so that the current of the battery can be effectively used, thereby increasing the mileage of the electric bicycle. Since the commercially available controller is a single closed-loop control system and relies on the current-limiting function of the MC33035 (MC33033) chip, the controller often outputs a large current to the current-limiting protection operating state during startup and acceleration.
3.Undervoltage comparison is designed as voltage hysteresis self-locking comparison Some controllers on the market only have the function of under-voltage protection, that is, when the battery voltage is lower than a certain voltage value (such as 32V), the controller is blocked from working. This makes it easy for users to use the battery's rising voltage to work (that is, after the battery stops discharging , The battery voltage will rise by 2~3v), causing the battery to over discharge. The controller undervoltage comparison is designed as a voltage hysteresis self-locking comparison, which can effectively avoid the use of battery pick-up voltage. The Wheelchar brushless motor and brushless electric vehicle controller designed according to the above improvement has been tested by various load conditions and various road conditions, and it has proved its high reliability. Reliable protection can be achieved in the case of locked-rotor operation and direct short circuit of the output terminal, which improves the reliability of the brushless electric bicycle controller in actual operation. The improved controller can completely reduce the failure rate of the controller and reduce The purpose of the vehicle repair rate. In addition, due to the function of the current loop, it can extend the driving distance by nearly 10% compared with the general controllers on the market, and the effect of the current loop is more obvious when there are frequent accelerations and decelerations and repeated up and down slopes during driving